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I have an extra EA82T with no internals and a crossmember from another turbo car. I assembled it on the engine stand including the parts that will effect clearance on the header/uppipe when it is installed.

Need to secure the turbo to the engine so when I cut the pipe away and leave only the flanges the turbo won't move and effect placement when I weld it all together.

Haven't gotten too far along with this project but will update if anyone shows interest.

Extra greasy! Need to completely attach the motor mounts. Coolant lines, oil lines, check power steering lines on the RX to see if they are going to be in the way. Have alot to do before I start welding.

Constructive input and ideas would be much appreciated. When I was doing the FMIC some of you guys helped more than you realize with your input.

Oh yeah. Going to mimic the equal length headers I've seen others make in the past. TWE and a few on the BYB. Not too many ways to build them equal length or close considering the space limitations.
I'm sure someone will bark out that I'm copying a TWE header or something of that nature.
Imitation is the sincerest form of flattery I say.

I'm not one to drop 400.00 into a set of headers either.

Still looking for the math to find out what is optimum size pipe dia. and length.

instead of equal length, try tuned length. the way thesse engines arelayed out, its easier to go tuned instead of equal. tuned is where one side is twice the length of the other, but it evens out the pressure like equal, just sounds better. that and you would have to make fewer bends. look at the borla headers for the ej22, its only a two pipe header, but its the same design as what im talking about. another ting you could di is to make a removable uppipe so that you wont have to make a new header or chop the new one if you decide to change turbos.

I could see why you would imitate the TWE header. It's already been done and you know it works. I would think that it is pretty much equal length based on the sound alone. My car sounds nothing like anything 'boxer' like the Borla header does for the 2.5RS or even the WRXs. The sound is raspy, almost motorcycle like. My wife says it sounds like a motorcycle is coming down the street when I pull up. Maybe I should do some sound bytes so you know what I'm talking about.

Here is a picture to help you get started.

If you look close enough, you can tell it is not exactly equal length. It gets the job done though. Perhaps a tuned length header is possible if the drivers side exhaust pipe does not go towards the back but rather the front. I dunno. Space is tight either way. Good luck!

I've done a very similar thing, and the best bits of advice I can think to give are

-Spend plenty of time equalizing length in your mockup, get it as close as possible, use centerline radius is the accepted way that I know of.
-.050" anti reversion step at the head port exits
-Burns 2-1 merge: expensive, but you will see a huge improvement over anything you (or twe) could make, #1 thing that is worth the money imo. This will also get you tighter through the crossmember.
-Slipjoints: at the merge and I did/am doing on in the center front on the long tube. Cracking is not good (I am using stainless, expansion = mucho)
-Don't waste time worrying about acoustic resonance formulas, they are not generally useful on street cars, and they are not even 'right' they will get you close but empirical testing must be done to make proper use of wave tech, which means a lot of time and $$ for a little gain/small rpm range. There are far too many variables in the exhaust to lock down such complex things into a formula.

People might accuse you of copying the TWE header, but since TWE's header is just a variation of what others have been doing at ausubaru/everywhere else for years there is no basis for that claim. I don't know who came up with the 'original' design probably Subaru Rally in the 80's. Either way it is hardly unique or special, it is the simplest design that gets the job done in the space we have.

And good luck! Remember some of the best performing header designs really were mistakes or errors, not some computer calculated number crunched feat of mankind.

Haven't cracked a book yet. Just had to pull the pizza guy from the edge of the new driveway. he ripped a big chuck of new asphalt loose. Yay.

Suby, thanks for the tip about the tuned vs equal. I will look for a good picture of the EJ header.

Myx, I do want mine to sound like a boxer, but it's not that important. Special thanks for the picture and the advice.

Built the majority of the jig to hold the turbo in place when I cut the exhaust pipes off the flanges. Chunks of scrap steel and some quick welds. Need to put the 45's in and call it done for tonight.

It would be bad to go through all this trouble and build something that won't fit on the RX because the turbo mount sagged when I was fabbing it up.

Shadow- Couple Q's from your post.

*Centerline measurements- on that.*Step from head into pipe- That's going to come from using the original flanges. Might even have to open them up a bit.*Burns 2-1- I'm not following you on this one.*Slipjoints- I'm going to weld it in and see what happens. Don't want to have any of the piping crack but doing it with the grassroots frame of mind.The downpipe has been in for a year and hasn't failed as of yet. It's solid from the turbo out to the back.

Have thoughts on the 1 3/4" piping and how it will effect boost onset?

Appreciate all the other advice. I'm probably going to find pictures of some good designs and measure as best I can then go to welding.

I'm planning on using 1 3/4" piping because I have about 20' of it left from the FMIC fab.

I don't want to go too big because I still want the bottom end. I might change a bit when I find my math.

Jay

Jay, 1.75" is that ID? I'm going to fab. a header up for a turbo gl-10 4x4 coupe, I already have 2 TWE header/dp's on my wagon's. I can't remember the I.D. of the header but it's too big IMO. Top ends great and all but I'd rather get the top end from a larger turbo [like my tdo4] not from oversize header pipes. 1 3/4" sounds too big to me, I'm going to see if I can find some 1.25" ID tubing for my header and use my twe pipes as a guide for the design. Just a thought.

As for tubing size, if one was just guessing 1.75 would seem awfully big, I'm not sure on the TWE pipes but they are around that size, and from the emprical results seem to perform fairly well on the low and mid range. From what I have read and applied (perhaps incorrectly who knows) 1.375 is a good all around size for the tubes, but the EA82 is kindof convoluted anyway because it shares 2 cylinders... I am using 1.5, I figure if there are a few of us making them, we use different tubes, get different results and compare.

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it.
MY piping for this project is 2.75 O.D.

I don't much care about top end, I'm looking for power in the bottom, mid range.

Anyone running the TWE header with a 260* Delta cam? When does that come into the boost? Mine starts at around 2650 and pull right up until redline. Factory boost. I would like to keep it there or get a bit lower, say 2500. Top end does not matter to me.

So a big cam in a naturally aspirated, slightly overcarburated, lightened flywheel, strong clutch, rear wheel drive, sub 2600 lb, 245/50 15 shod car would get me what I want. And the instantanious throttle response would be nice too.
A Miata with a built 5.0 out of a Mustang would probably fit the bill. Rear from a Thunderbird. Anyone want to buy an RX? I'll finish the header before you pick it up.

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it. MY piping for this project is 2.75 O.D.

How did you measure the pipe? The heat shielding makes it look much bigger than it is. And there is a MAJOR neckdown at the turn up towards the turbo. (I believe that it was rallyruss that discussed the actual pipe sizes, and how narrow that neckdown was.)

Measured with the exhaust off the engine, across all three openings of exhaust.

Spent a little time today with a cut-off wheel getting the heat shields away from the factory pipe. I was surprised to learn they have cloth material in them for insulation.
I don't remember the 87 having it. this pipe is from an 88.

oh and you might want to have the weight of the engine and such ON the crossmember instead of the crossmember stretching the engine mounts down....that way you can properly clearance the header from engine/crossmember.

Do you recall OD/ID on the TWE? You don't like my solid DP? Whatsamattawifyou! Itsaperty!

Read the whole post about the motor mounts. Might get a ratchet strap and cinch the motor and crossmember together for fitment sake. I'll eventually get under the RX and see if I missed anything else that might get in the way.

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it. MY piping for this project is 2.75 O.D.

I don't much care about top end, I'm looking for power in the bottom, mid range.

Anyone running the TWE header with a 260* Delta cam? When does that come into the boost? Mine starts at around 2650 and pull right up until redline. Factory boost. I would like to keep it there or get a bit lower, say 2500. Top end does not matter to me.

So a big cam in a naturally aspirated, slightly overcarburated, lightened flywheel, strong clutch, rear wheel drive, sub 2600 lb, 245/50 15 shod car would get me what I want. And the instantanious throttle response would be nice too. A Miata with a built 5.0 out of a Mustang would probably fit the bill. Rear from a Thunderbird. Anyone want to buy an RX? I'll finish the header before you pick it up.

Tomorrow is another day and I won't order pizza.(See previous post)

Jay

I've got the 260 cams with the TWE header. Comes on full boost at hits hard right around 26-2700. However, in first gear it gets up there really, really fast. Redlines almost instantly, then, when you shift, it's right in the powerband

Ave, That's what I want to hear. First gear in mine is like that too. Especially in L range.
WJM, just because it will rev to 7500 doesn't mean you should. Remind me never to let you drive my car. It would shock the old girl to be beaten on that hard.
Jay

Ave, That's what I want to hear. First gear in mine is like that too. Especially in L range. WJM, just because it will rev to 7500 doesn't mean you should. Remind me never to let you drive my car. It would shock the old girl to be beaten on that hard. Jay

The only ones that went to 7500 was my wagon and the first RX i had. Wagon went to 7500 just once. The RX 3 times. Otherwise, I always shifted at 6k with the cams. 5500 with stock cams.